In the metals producing industries, a refining operation may be carried out by blowing gases into molten metal contained in a vessel. Impurities are removed by chemical reaction and go into a slag or are emitted in gaseous form from the vessel. A hood may be located over the mouth of the vessel to draw off the gases and conduct them to pollution control equipment. To further reduce escape of gases to the surrounding work area, an enclosure is sometimes erected so as to surround the vessel and confine the gases to an area where the hood effectively may remove them. Such an enclosure is commonly used in the steel industry to surround a BOP or Q-BOP metallurgical vessel.
The enclosure is generally constructed of two or more abutting wall members which are of heavy steel construction. One or more of the wall members is movable so that an opening may be created to expose the vessel and permit charging of materials therein. When the wall members are closed and the refining operation progresses, gases may escape from between a movable wall member and its abutting wall members unless a tight abutting fit is provided. In past practice, no special seal was provided to prevent this escape of gas; the seal depended upon a tightly abutted joint between adjoining edges of the abutting wall members. Due to the heavy steel construction of the wall members, heat radiated from the vessel causes warping along the adjoining edges of the wall members and prevents obtaining a tightly abutted joint. This effect becomes accentuated as operating time progresses which permits more gases to escape to the surrounding work area. Another factor is that the slag and molten metal splash from the vessel and collect on the adjoining edges of the wall members and further prevent a tightly abutted joint.
Applicant is not aware of any prior art showing a sealing means between a movable wall member of an enclosure for a metallurgical vessel and an abutting wall member. However, seals have been provided in metallurgical furnace structures such as heat treating furnaces and annealing furnaces where protective atmospheres are used.
A seal is shown in U.S. Pat. No. 2,354,127, Krauscope, between a movable floor or bottom of a heat treating furnace and the furnace walls. The movable floor has a trough around its periphery containing an asbestos gasket covered by a sheet metal strip. The asbestos gasket is supported on a plurality of spaced springs, each mounted over a rod mounted in the trough. A plate surface mounted on the bottom of the walls of the furnace contacts the sheet metal strip as the movable floor is closed and compresses the asbestos gasket. The sheet metal strip has V-notches in its sides to permit flexible bending when it contacts the plate surface of the walls. The asbestos gasket serves to fill in between the notches of the sheet metal strip as it flexes. This seal prevents gaps due to warping of the floor or walls of the furnace only to the degree that the sheet metal strip is flexible enough to follow the contour of the warped areas.
Another seal is shown in U.S. Pat. No. 3,179,394, Sims et al, between a base section and a cover for an annealing furnace. A flange extends vertically from a trough around the periphery of the base and contacts a resilient material mounted around the periphery of the cover. The weight of the cover presses the flange into the resilient material which is either solid or sponge rubber or neoprene, resilient plastic, etc. Since the cover becomes hot, cooling water is provided against a plate covering the back of the resilient material. A secondary seal is also provided on an outer periphery from the first seal. The resilient material is located in the cover so as to be protected from scale or other foreign materials which might prevent an effective seal. This seal is limited to locations between a base and a cover and does not teach use of a resilient material along a vertical edge of a wall member.
We have found that a heat resistant resilient material may be used for a seal along the vertical edge between two wall members and that cooling of said resilient material is not necessary. We have also found that such a seal may be maintained regardless of warping of the edges of the wall members and buildup of foreign materials along said edges.